What is exponential growth?
- when the growth rate of a population increases rapidly over time
What are the three phases of population growth?
LAG phase - the period of time in population growth when an organism is adapting to its new environment and growth is slow
LOG growth - when the growth of a population increases rapidly over time
STATIONARY phase - when the growth of a population has slowed to zero
PLEASE refer to pg 175 for graphs
What is carrying capacity?
- is the maximum population size of any specie that the environment can support without any damage in terms of food, water and other resources
- populations have expected to stop growing at soem point
- in nature, after exponential growth the population fluctuates up and down (compared to lab)
- if natural limits on population are not present - the population size may exceed the carrying capacity
- humans have consistently managed to exceed carrying capacity of every area in which they live - survive due to advancements in tech and food
Describe hte history of human population
- 600 years ago humans started to grow crops+keep animals - hunter gatherers - population began to grow
- by the time the modern system of counting began 2000 years ago - population was 250 million
- in another 1800 years we reached 1 billion
- growth became very rapid
- in 1930 - 2 billion
- 1975 - 4 billion
- 2016 - 7 billion
- 2024 - 9 billion
- we see no signs of levelling off in human population
- animals level off humans show no signs of doing so
- human pop expected to settle into equilibrium and level off
What is birth rate and death rate?
BIRTH RATE - the total number of live births over a certain period of time
formula number/1000 multiply by 365
DEATH RATE - the total number of deaths over time in an area
What is natural increase?
the birth rate minus the death rate
What are some factors affecting birth rate?
- LEDC - high death rate also have high birth rates - infant mortality rates
- in agrarian (farming) economies of many LEDC’s more people are needed for manual labour and so families tend to be larger
- in MEDC’s it is expensive ot have children and pensiosn are provided by state
- social and political factors result in low use of birth control in LEDC’s whereas in MEDC’s birth control is widely used so both birth and deah rates are lower
what is the population growth formula?
pop growth = (birth rate+immigration) -(death rate + emigration)
what is the difference b/w immigration and emigration?
immigration - people entering an area from outside
emigration - people leaving an area from inside
Write some push factors for rural to urban
- drought/famine
- poverty
- poor links with outside world - telecommunication
- poor services
- work on the land only, susbsistence
- desertification
- sea level rise
- seasonal weather events such as monsoons, cyclones etc
list some rural to urban pull factors
- good supplies of food despite weather
- well paid jobs
- hospitals, schools, water, electricity
- factory, shop, office work for a wage
- employment
What is population density
- the number of people living in a population in a defined area
- worked out by dividing number of people living in a place by the area of that place
- avg density of huamsn is about 50km(-2) of land
- highest - Monaco 26000km(-2)
- lowest - Greenland 0.03km(-2)
pg 180-1
What is population distribution?
- is how the population is spread over an area
- where population of people do or do not live
pg 180-1
What is a population pyramid?
- it displays populatino structure in terms of age and sex
- a diagram that shows the proportion of population that is male and female in different age groups
What are the three main categories that population pyramids fall into?
- Expanding or young populations - eg Afghanistan - high proportion of young people because of a high birth rate - usually low life expectancy - triangle shape
- Stationary Populations - USA - rectangular shape except at top where people die
- Contracting/declining or old population - Japan - Populatino declining because of low birth rates - low death rates - inverse triangle
pg 182 for diagrams
How can family planning be used to manage populations?
- promoting and teaching about family planning
- family planning centers
- providing and spreading awareness about contraceptives
- allowing sterilisation and abortion to be practiced
- application of IVF - in vitro fertilisation
- provide free contraceptives
How can improved health and education help in managing populations
- education makes peopel aware of family planning and contraceptives
- educated women may be more career oriented limiting hte children born
- education can lead to later marriage and prevent child marriages
- low infant mortality rate due to better healthcare - couples have less children then
What are pronatalist and anti natalist policies?
PRONATALIST
- aims to encourage couples ot have children
- for eg in France - parents are aid the equivalent of minimum wage for a year after they have a third child - also have subsidised train fares - pay less tax - subsidised day care
- can help by subsidising healthcare and educatino for children
ANTINATALIST
- aims to discourage couples from having children
- china one child policy
